Question

三個(gè)植樹(shù)隊(duì)，第一隊(duì)植樹(shù)a棵，第二隊(duì)植的樹(shù)比第一隊(duì)的2倍少25棵，第三隊(duì)植的樹(shù)比第一隊(duì)植樹(shù)的一半多42棵，問(wèn)三個(gè)隊(duì)共植樹(shù)多少棵？并求當(dāng)a=100棵時(shí)，三隊(duì)共植樹(shù)的棵樹(shù)．

Answer 1

∵第一隊(duì)植樹(shù)a棵，第二隊(duì)植的樹(shù)比第一隊(duì)的2倍少25棵，
∴第二隊(duì)的植樹(shù)棵數(shù)為：2a-25，
∵第三隊(duì)植的樹(shù)比第一隊(duì)植樹(shù)的一半多42棵，
∴第三隊(duì)的植樹(shù)棵數(shù)為：

1

2

a+42，
所以三個(gè)隊(duì)共植樹(shù)：a+2a-25+

1

2

a+42=

7

2

a+17．
當(dāng)a=100棵時(shí)，三隊(duì)共植樹(shù)的棵數(shù)為：

7

2

a+17=

7

2

×100+17=367（棵）．